Chapter One
1 - 4
Introducing ASCO Load Banks
ASCO load banks are purpose designed to provide all of the facilities needed to quickly,
safely and reliably test generating equipment with outputs up to several megawatts.
Figure 1-2
ASCO Sigma LT load bank core components
There are variations between different ASCO Sigma LT load bank models, but Figure 1-2
shows a simplified schematic of the core components to be found in most units.
The diagram contains:
•
An array of load elements grouped in small steps that are individually activated by
switchgear to allow the load applied to the generator to be precisely controlled.
•
A fan and duct forced air system which ensures that the heat generated during testing
is vented safely to atmosphere.
•
Fuses and safety interlocks that ensure that the test can be shut down in a controlled
fashion if any problems occur.
•
Automatic precision control of the test and allow the results to be displayed with
better than 0.5% accuracy.
Cold air
inlet
Fan
motor
Fan
contactor
Air duct
Step 1
Step 2
Step n
Hot air
outlet
Load elements
Sigma LT
Digital Toggle
Switch Control
Load
contactors
Fuses
Current
Transformers
External supply for
fan and controls
Supply-on-Test
Sigma LT
Hand-Held
METERING
MASTER
LOAD
5 kW
5 kW
10 kW
10 kW
25 kW
50 kW
50 kW
50 kW
REMOTE
LOCAL
ON
MODE
!
V/Hz/kW
V x 3
A x 3
LOAD
SELECT
R
ASCO
3000 Series
Introducing ASCO Load Banks
1 - 5
ASCO Load Bank Control Options
Reliable testing requires precise control of the load applied to the generator and accurate
real-time measurement of the generator’s output. To achieve this, ASCO Sigma LT load
banks are fitted with a control panel and have the option of a hand-held control. Sigma LT
is a microprocessor-based control and instrumentation system specifically developed for
load bank applications.
Sigma LT Digital Toggle Switches
Sigma LT digital toggle switches are fitted as standard to all Sigma LT Load banks. Digital
toggles provide local, resistive only load testing with single and three phase instrumentation
on a seven segment display.
Sigma LT Hand-Held
The Sigma LT hand-held connects directly to the load bank to provide remote control and
enables up to 25 load banks to be connected into a single network.
METERING
MASTER
LOAD
5 kW
5 kW
10 kW
10 kW
25 kW
50 kW
50 kW
50 kW
REMOTE
LOCAL
ON
MODE
!
V/Hz/kW
V x 3
A x 3
LOAD
SELECT
R
ASCO
3000 Series
399 8 49 9 70 0
